Heavy metal concentrations in sediments from the coast of Bahrain

Abstract

The concentration of lead, zinc, cadmium, nickel, copper and vanadium in the sediments of nineteen coastal stations in Bahrain were determined by atomic absorption spectrophotometer (AAS). The results showed widespread occurrence of anomalously high levels of heavy metals owing to pollution, especially, zinc and lead, and the overall mean value in sediments for Pb, Zn, Cd, Ni, Cu and V of 111, 104, 1.17, 40.5, 15.1 and 21.9 mg/kg, respectively. In certain areas, the concentrations of some of these heavy metals, especially lead, were much higher. This could be the result of pollution from land-based industrial and urban sources, namely automobiles, which contribute to the overall pollution in the coastal areas. Refineries and other industries, as well as sewage effluents, discharge their liquid wastes in the shallow coastal areas and are sometimes untreated or partially treated. Heavy metal concentrations in areas located near industries were generally higher than in the other regions of the island. The trend that has been noted in this study suggests that this pollution, if left unchecked, could pose a threat to mankind and to marine life. This study represents a limited number of sampling stations in Bahrain. To assess metal pollution in Bahrain and within the Arabian Gulf, and to establish a more realistic baseline, it is suggested that a more detailed study of metal concentrations in the sediments from the coastal areas of Bahrain be conducted.